The present invention relates to a charging control apparatus and a charging control method.
A battery for supplying power to electric components and an alternator for generating the power to charge the battery while an engine is operated are mounted on an engine-driven vehicle.
In a related-art charging control, as one of methods for rapidly charging the battery, an alternator adjustment voltage to adjust a voltage generated by the alternator is set to relatively high voltage when the vehicle is decelerated since the alternator can generate much power by regeneration thereof, thereby increasing the power generated by the alternator. In addition, the alternator adjustment voltage is set to relatively low voltage when the vehicle is accelerated since engine torque required for accelerating the vehicle is prioritized, thereby decreasing the power generated by the alternator.
While such a charging control, if the alternator adjustment voltage is suddenly changed from a high value to a low value and vice versa, a voltage of the battery connected to the alternator is also suddenly changed. The suddenly changing of the voltage of the battery may effect operation of the electric component mounted on the vehicle. For example, a light mounted on the vehicle suddenly flickers.
In order to prevent the voltage of the battery from being suddenly changed, in the related-art charging control, the alternator adjustment voltage is gradually changed to a target alternator adjustment voltage (see Japanese Patent No. 3044867, paragraphs [0017] to [0022]).
However, in the related-art charging control, for example, even in a case where the light is not used, the alternator adjustment voltage is gradually changed when the vehicle is decelerated or accelerated, so that charging efficiency of the battery is decreased.
On the other hand, with sudden spread of vehicles, needs for improving comportability, safety, and convenience of vehicles are increased. To satisfy the needs, the number of the electric components such as an air conditioner and a navigator which are installed in the vehicle is increased, thereby increasing electrical load of the battery. Therefore, it is necessary to control for charging the battery in order to prevent the battery from voltage reduction and deterioration.
However, in some cases, the charging efficiency of the battery is deteriorated according to condition of the battery. In order to overcome such a problem, in a related-art battery charging apparatus, the charging efficiency of the battery is determined from an open voltage of the battery and a regulator adjustment voltage to indirectly control a voltage output from the alternator is corrected based on the determined efficiency of the battery (see Japanese Patent No. 3010719). Namely, the related-art battery charging apparatus prevents the battery from an overcharging by correcting the regulator adjustment voltage according to the charging efficiency of the battery, thereby increasing the lifetime of the battery.
However, although the related-art battery charging apparatus controls the alternator to charge the battery according to the charging efficiency of the battery in order to improve the lifetime of the battery, it does not control the alternator in order to rapidly charge the battery.